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*** Study now complete. Outputs included at the bottom of this page.***


The study aims to quantify the burden of complications of gastrointestinal infections across society and to determine which factors are associated with development of complications. The study results will help us to develop new methods for studying other infectious diseases and their associated complications.

Why this is important:

It is currently estimated that around 25% of people in the United Kingdom suffer from an episode of gastrointestinal illness annually. Most people will recover from their illness without the need to visit their GP or use medication for their illness. But some people will eventually develop complications such as reactive arthritis, irritable bowel syndrome or Guillain-Barre syndrome with a small proportion dying from their illness.

It is currently estimated that around 25% of people in the United Kingdom suffer from an episode of gastrointestinal illness annually. 

As well as exposure to the infection other factors affect whether a person becomes ill and the severity of the illness that results. For example, drugs affecting the acidity of the stomach are thought to be important in the risk of gastrointestinal infection, and perhaps the severity of the resulting illness. Understanding these factors can guide interventions that complement controlling exposure to infections.


To form the study cohort, we will link people with a confirmed laboratory report on gastrointestinal infection held by Public Health England (PHE) to their corresponding consultation record following a visit to their GP using the Clinical Practice Research Datalink (CPRD). The study cohort will be further linked to the Hospital Episode Statistics (HES) dataset, the Office of National Statistics (ONS) mortality data file and the English Index of Deprivation 2010. These linkages will allow us to measure illness severity, treatment of patients and to determine if there are any socio-economic differences in the measurement of these risks. Linking electronic health records of patients is a reliable and cost-effective method to study multiple factors associated with a disease and sometimes the best approach to study rare conditions.

The acceptability for the use of patients' electronic health records in this manner was welcomed following consultations with patient and public involvement representatives.

How this could benefit patients:

Preliminary work on the development of complications following gastrointestinal infections suggests that most of these complications can be difficult to diagnose in particular reactive arthritis and irritable bowel syndrome. In addition, it can sometimes take up to six months before the complication arise making it difficult to attribute to an earlier acute infection.

As such, linking a patient's complete electronic health record will ensure early identification and diagnosis of their complication and the associated factors which contributed to the development of the complication.

This study is now complete

This study is now complete and the results have been shared in two published articles:

Incidence, risk factors, and health service burden of sequelae of campylobacter and non-typhoidal salmonella infections in England, 2000-2015: A retrospective cohort study using linked electronic health records. Esan OB, Perera R, McCarthy N, Violato M, Fanshawe TR.  J Infect. 2020;81(2):221-230.
Esan OB, Pearce M, van Hecke O, Roberts N, Collins DRJ, Violato M, McCarthy N, Perera R, Fanshawe TR. Factors Associated with Sequelae of Campylobacter and Non-typhoidal Salmonella Infections: A Systematic Review. EBioMedicine. 2017 Feb;15:100-111.

Further information:

Full title of project:

Estimating the burden of complications following common gastrointestinal infections and the remediable factors which contribute to the burden.

Length of project:

5 years.



NIHR Health Protection Research Unit in Gastrointestinal Infections

External collaborators:

Relevant pilot study:

Risk factors which contribute to the development of complications/chronic sequela following Campylobacter and non-typhoidal Salmonella infection.

External links:

WHO - Global burden of foorborne disease
> PHE - Gastrointestinal infections: guidance, data and analysis 
> NIHR - Health Protection Research Units
> NIHR - HPRU Gastrointestinal Infections